Since upgrade of i18n 1.6, it seems not support the menu item Translate and Localize.
"Translate and Localize. Menu items with language will allow translations. Menu items without language will be localized. "

Superfish only get the english main menu to display. before i18n 1.6 the funcation i18n_menu_localize_tree will get the English main menu to be localized. After i18n 1.6, many user now use fixed language and create main menu for each language. In this case, superfish still use the English main menu, and i18n_menu_localize_tree will not localize it anymore As the Menu menu not have any localize menu items anymore.

With this patch, it will let superfish to use Main Menu for English and Main Menu CN for Chinese, Main Menu DE for Germany.

The only thing that has changed in i18n 1.6 is that node menu items are not filtered out using node access anymore. So you need to use i18n_menu_localize_tree to get your menu items filtered out by language and localized.

Multilingual / localized menus are working as they were before and i18n_menu_localize_tree should still be working. So we should be able to localize superfish menus using i18n_menu_localize_tree, which Superfish 1.9-beta4 does.

If not maybe there's a bug we should fix on i18n?

About the menus / variables yes, I see the problem which I think is superfish using variables to store block settings and multilingual variables not supporting such thing.